In International Patent Applications WO 01/67964 and WO 02/39909 by the applicant of the present application, the descriptions of which are incorporated herein by reference, there are described an articulating endoscope containing a surgical stapler for performing fundoplication procedures for the treatment of gastroesophageal reflux disease (GERD). The stapler consists of two parts, an anvil unit and a staple cartridge unit that are laterally distanced from each other along the axis of the endoscope. In the preferred embodiment of the invention, as disclosed in these applications, the staple cartridge unit is located in a recess in the insertion shaft of the endoscope adjacent to the proximal end of the articulating section, which is located in the esophagus of the patient, and the anvil unit is located in the distal tip of the endoscope at the distal end of the articulating section located in the stomach.
During the endoscopic fundoplication procedure the distal tip is moved relative to the cartridge along a path that is a portion of a circle. As the distal tip approaches the cartridge, layers of tissue of the esophagus and stomach are pressed together. At this stage the staples are fired to connect the layers of tissue together. It is imperative that the final stage of bending of the scope should end such that the distance between the cartridge and anvil and their relative alignment are exactly the distance and alignment required for the legs of the staples to properly curl in the depressions on the face of the anvil. Not achieving proper distance and alignment of the distal tip relative to the cartridge will prevent the tissue from being correctly joined preventing successful completion of the procedure and can potentially pose the risk of serious harm to the patient.
FIG. 1 and FIG. 2 schematically show the distal portion of the insertion shaft of the endoscope described in these PCT applications with the articulation in the straight and fully bent configurations respectively. Shown in these figures are distal tip 10 attached to the distal end of articulation section 14 and the flexible part of the insertion shaft 16 attached to the proximal end of articulation section 14. A staple cartridge unit 18 comprising one or more arrays of staples and a staple firing mechanism are located close to the proximal end of articulation section 14 in a hollowed out portion of a rigid section (not shown in the figures), which connects the insertion shaft 16 to the articulation section 14. A stapler anvil unit 20 is located in distal tip 10.
FIG. 3 schematically shows an illustrative distal tip 10 with anvil unit 20 in place. The five pairs of depressions 22 in which the legs of the staples curl when the staples are fired from the cartridge can be seen on the anvil unit face. Also seen on the face 12 of distal tip 10 are a channel 24 that can be used for example for suction, irrigation, or a working channel, an imaging channel 26, and the distal ends of illumination fibers located in areas 28. The skilled person will understand that other options can be provided and other configurations are allowed depending on the requirements of the endoscopic procedure to be performed. As one example, a transducer, receiver, or reflector can be placed at one of positions 28 for use in ultrasound positioning as described below.
A major technological problem that had to be addressed in the design and in the surgical use of this device is that of achieving and verifying the proper alignment and distance between the two parts of the stapler. Alignment of an object is defined herein as the position and orientation of the object in some coordinate frame, i.e. three translations and three rotations. The term “correct working relationship” is understood herein to mean that the anvil is brought into the exact position opposite the cartridge and that the correct orientation and distance is reached between the face of the anvil and the face of the cartridge that will allow the legs of the staples to enter the depressions provided on the face of the anvil and to be properly curled to hold the layers of tissue being stapled together.
The correct functioning of the endoscopic device depends on the articulation section performing precisely as designed to bring the two parts of the stapler into the correct working relationship as it is bent with a fixed radius R (see FIG. 2). In the early stages of the development of the GERD endoscope it became apparent that it was very difficult and expensive to manufacture a vertebrae section that would consistently perform as required over repeated uses. Even if very precisely designed and manufactured, with time unwanted freedom of motion, or “play” due to “wear and tear” on the individual vertebrae caused by repeatedly bending and straightening the articulation section made the task of attaining the correct working relationship a difficult one.
As said, one of the major technological problems that had to be addressed in the design stage and especially during the surgical application of the endoscopic device was that of achieving and verifying the proper alignment and distance between the two parts of the stapler.
Various solutions to this problem have been suggested and tried by the Applicant. One solution is to provide two locking pins or, preferably, screws that are stored in the anvil portion and can be extended through holes 30 in the face of the anvil (FIG. 3) to engage and lock or be screwed into matching receptacles (not shown in FIG. 3) on the cartridge. When engaged the locking screws not only insure that the correct working relationship between the staple cartridge and anvil has been achieved but also hold the two parts of the stapler together to prevent them from being forced apart during staple firing.
In order to assist in bringing the face of the anvil close enough to the anvil with the proper orientation such that the screws can be extended from the anvil and enter the holes on the cartridge to complete the alignment, an ultrasonic positioning system comprising components on the anvil, cartridge, or both is provided. In International Patent Application WO 02/068988 by the applicant of the present application, the description of which is incorporated herein by reference, there are described ultrasonic techniques that can be used to accomplish the positioning.
Another approach to aiding in achieving the correct working relationship is described in International Patent Application WO 2005/115255 by the applicant of the present application, the description of which is incorporated herein by reference. In this approach, the cartridge and anvil surfaces are given matching curved surfaces. Additionally the curved cartridge surface has a two level structure. As the face of the anvil approaches the surface of the cartridge the tissue to be stapled is pressed between them; and, as a result of the structure of the cartridge surface and the curvatures of both surfaces, the curved surfaces slide over each other pulling the anvil into alignment simultaneously in both the longitudinal and the transverse directions.
It is a purpose of the present invention to provide systems and methods for achieving the correct working relationship of the two parts of a surgical stapler that is an integral part of an articulated endoscope, wherein the anvil of the stapler is located in the distal tip at the distal end of the articulation section of the endoscope and the stapler cartridge is located adjacent the proximal end of the articulation section of the endoscope.
Further purposes and advantages of this invention will appear as the description proceeds.